The only thing between the Sabres and another defeat was 25 meaningless seconds. Most of the fans had left. Buffalo was done.

Rasmus Dahlin wasn’t. He threw himself into 6-foot-3, 220-pound Radek Faksa. Despite taking the brunt of the blow, the Sabres defenseman kept the puck in from his knees and tossed it toward the net.

It didn’t matter. As the clock expired and Dallas skated to goalie Ben Bishop to celebrate the shutout on Tuesday night, Dahlin turned his back to the scene. He raised his stick above his head and came down with the thunder of Thor.

“Yeah, that was pretty stupid,” he said a day later. “You have to get it out of your body, but that was pretty stupid.”

Why? People understand that the 18-year-old competitor hates to lose. Why was that stupid?

“I have to learn,” Dahlin said. “I just need to handle my frustrations. It’s pretty tough to just have it inside, so you just want to get it out of your body. It’s...